As means for controlling electronic equipment such as household electric appliances, a large number of types of devices are employed, such as switches, buttons, touch pads, mice, and remote controllers. Operations in a contact method using switches, buttons, or the like have a drawback in that an operator is required to move to vicinity of the electronic equipment. The noncontact method using a remote controller or the like also has various inconveniences, drawbacks and/or the like, such as necessity of a remote control transmitter, necessity of searching for the remote control transmitter before operation, especially, in AV (Audio Visual) equipment, necessity of washing dirty hands for cooking equipment, extremely high risk in operation of a remote controller of a car navigation device by a car driver, and the like. In addition, touch pads, mice, and the like, which are instruments for operating electronic equipment, have any of such inconveniences as discussed above. To cope with such problems, techniques have been proposed that control electronic equipment on basis of detection of a motion of a human, a hand or the like in noncontact manner.
Techniques of controlling equipment on basis of a shape, a motion or the like of an imaged hand have been proposed in Patent Literature 1 (JP 2004-78977 A), Patent Literature 2 (JP 2007-164814 A), and Patent Literature 3 (JP 2008-250774 A), for instance. Patent Literature 4 (JP 2006-99749 A) has proposed a system in which a characteristic image (e.g., of a hand) is extracted from an image with distance information obtained with a wide angle by use of a distance image and in which a motion of an operator is detected on basis of the distance and the image. Patent Literature 5 (JP 2006-260574 A) has proposed an optical navigation system in which a quantity of movement is determined by comparison between a reference image picked up and the next pick-up image data.
In Patent Literatures 1 through 3 mentioned above, however, requirement of image recognition processing for recognition of an imaged subject as a hand, image signal processing for analysis of a motion of the hand, and the like leads to requirement of a sophisticated signal processing system for coping with various patterns and results in a high cost for a control device for controlling electronic equipment.
In Patent Literature 4, the recognition can be improved by provision of an image with distance information. However, a TOF (time of flight) system is employed for measuring the distance information for individual pixels. Thus the system not only requires extremely high speed signal processing for measuring round-trip time of light but makes indispensable a high output power light emitting source for ensuring obtainment of a sufficient SNR (Signal to Noise ratio:S/N ratio) for each pixel. As in Patent Literatures 1 through 3, furthermore, image signal processing is required therein and thus involves the system with a large size and a large cost for a device for controlling electronic equipment.
Patent Literature 5 involves a large cost, as is the case with Patent Literatures 1 through 3, in that image signal processing is required for extraction of the quantity of movement by comparison between the images.